1. Field of the Invention
The present invention relates to a digital data input/output circuit, and more specifically to an input/output circuit for use in an input/output port of a memory and capable of sending and receiving a digital data in different formats.
2. Description of Related Art
So-called digital data input/output circuits have been used in various fields of data processings. On the other hand, the format of data processed or transferred is different in apparatuses or systems being used. For example, a serial data is handled in one field, and 4-bit parallel data is transferred in another field. Further, 2-bit parallel-serial data transmission is performed in still another field. Therefore, the input/output circuit is desired to comply with different formats or modes of data. However, conventional input/output circuits cannot handle two or more different formats or modes of data, and in addition, the input/output circuits have been complicated although the circuits can handle two different formats or modes of data.